(a) Field of the Invention
The present invention relates to an actuator linkage and more particularly to a damped actuator linkage for use on underwater vehicles for reducing the transmission of noise and vibrations.
(b) Statement of Prior Art
Actuators are used in a variety of underwater vehicles such as submarines and torpedoes for providing the torque required to turn a control steering fin. Typically, this torque is transmitted to the fin shaft via a linkage. Current linkages used for this purpose are solid metal. While they function adequately as force transfer mechanisms, they also transfer acoustic energy which eventually finds its way into the water as radiated noise. This noise path is significant in those situations where it is desired to reduce the detectability of a vehicle. Linkagesor couplings containing non-metallic components are known in the art. U.S. Pat. No. 3,879,959 to Clampett, for example, illustrates a flexible coupling for connecting a steering shaft to a steering gear. The coupling includes identical interchangeable first and second stamped metal yokes of a generally U-shape. The yokes are nested together with a rubber member interposed therebetween. The rubber member has a plurality of outwardly extending flanges which engage the yokes and provide a driving connection from one yoke to another.
U.S. Pat. No. 4,232,563 to Peterson et al. illustrates end bearing assemblies for articulating links such as control links associated with helicopter rotor mechanisms. The end bearing assemblies comprise at least two elastomeric bearing sections connected by a load-transmitting member and are arranged to react to loadings and accommodate motions along and about at least one of three mutually orthogonal axes. The bearing sections are formed by interleaving elastomeric material and metal shim layers.
It is know in the art to provide shock absorbers on propulsion devices for water vehicles. U.S. Pat. No. 4,642,057 to Frazell et al., for example, illustrates one such propeller wherein an elastomeric shock absorbing member is interposed between the hub carrying the propeller blades and the propeller shaft. U.S. Pat. No. 4,938,723 to Yoshimura et al. illustrates a similar arrangement.
U.S. Pat. No. 4,747,796 to Iwai et al. illustrates a coupling device for marine outboard drives for providing a coupling between an engine output shaft and the outboard drive. In certain embodiments shown therein, elastomeric elements are used to provide the driving connection.
None of these linkages however are designed specifically to be used on an underwater vehicle for controlling utility devices such as steering fins and for attenuating the acoustic energy produced by the actuator itself.